Rheostatic controller for electric motors.



F.D.HALLOGK. RHEOST ATIO CONTROLLER FOR ELEGTRIG MOTORS.

APPLICATION FILED JAN. 3, 1910.

958,805. Patentd May 24, 1910.

QOQQ G O TTORNEY UNITED STATES OFFICE.

FLETCHER D. HALLOCK, OE PITTSBUKG, PENNSYLVANIA, ASSIGNOR. TOWESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY,YA CORPORATION OFPENNSYLVANIA.

RHEOSTATIC CONTROLLER FOR ELECTRIC MOTORS.

To all whom it may concern:

Be it known that I, FLETCHER D. HAL- LocK, a citizen of the UnitedStates, and a resident of Pittsburg, in the county of Allegheny andState of Pennsylvania, have invented a new and useful Improvement inRheostatic Controllers for Electric Motors, of which the following is aspecification.

My invention relates to rheostatic controllers for electric motors andit has for its object to provide a device of this character that shallbe adapted to regulate both the armature and field resistances of electric motors and that shallcomprise two contact arms, one of which isadapted to govern the other.

. In my co-pending a plication, Serial No. 536,055 filed of even ateherewith, I have illustrated and described a regulating rheostat forelectric motors comprising a pair of contact arms which may bemechanically interlocked for concurrent operation in both directions,the arrangement of parts being such that one of the arms may be releasedfrom the other and independently operated.

According to my present invention, I provide two arms which correspondto those in the application just referred to, but, instead of themechanical interlock, I provide an electric circuit switch on one arm bywhich an electro-magnet, that governs the position of the other arm, maybe controlled. In this arrangement, one of the arms is provided with aretracting springan electro-magnet being provided for holding the arm inopposition to the spring in any of the controller positionsand thesecond arm is provided with an operating handle and is adapted to carrythe first arm with it in one direction but may be adjusted independentlyof the first arm in the opposite direction.

Figure 1 of the accompanying drawings is a front elevation of acontroller constructed in accordance with my invention. Fig. 2 is afragmentary view at right angles to Fig. 1 showing the outer end of oneof the arms, and Fig. 3 is a diagrammatic view showing the circuitconnections for the controller of the other figures.

Referring to Figs. 1 and. 2 of the drawings, the structure here showncomprises a slab or face plate 1 of insulating material on which aseries of armature-resistance contacts 3 and field-resistance contacts 2are Specification of Letters Patent.

Application filed January 3, 1910.

Patented May 24, 1910.

Serial No. 536,053.

mounted, a pair of contact-bearin arms 4 and 5 and an electro-magnet 6.T e arm 4 is retracted to its off position by a spring 7 and is held inthe other control positions by the electro-magnet 6 except when themotor circuit is interrupted, as hereinafter pointed out. Both of thearms 4 and 5 are rotatably supported on a stud 8 which projectsoutwardly from the plate 1 and the arm 5 is provided with a projection 9which is adapted to engage a rib 10 of the arm 4 so that when the arm 5is rotated in a clockwise direction, the other arm is carried with it inopposition to the spring 7.

As shown in Fig. 2, a switch 11 is provided at the outer end of the arm5 and is normally closed, but may be opened by a push button 12 whichprotrudes from the end of the handle 13 that is carried at the outer endof the arm. The switch 11 is located in the circuit of the magnet 6 and,consequently, in operating the controller, the electro-magnet may bedeenergized at any time by actuating the push button 12. The contacts 2and 3 are arranged substantially in concentric arcs of circles and arerespectively engaged by contact fingers 14 and 15 on the arm 5. Acontact ring segment 16 is also mounted on the face plate 1 and isengaged by the contact finger 17 of the arm 4. The structural details ofthe push button switch 11 form no part of my present invention, andother switching devices may be substituted therefor. As shown, the operating handle 13 is provided with a hole 18 through which a rod 19extends, the outer end of the hole being counter-bored to receive aspring 20 and the push button 12. The inner end of the rod 19 is securedto the contact finger of the switch 11 and its outer end is secured tothe push button. The electro-magnet 6 corresponds to that shown in myco-pending application, Serial No. 437 ,324, filed June 8, 1908, and isprovided with a ball or sphere 21 to engage any one of a series ofcounter-sunk holes 22 in a segment 23 which is secured to an enlargement24 of the arm 4 and with a core or armature which acts against the ballwhen the electro-magnet is energized. The arrangement of parts is suchthat the arm 4 is not locked in any position so that it cannot be moved,but the action of the electro-magnet is suflicient to overcome theretracting effort of the spring 7.

The operation of the device and its circuit connections may best beunderstood by referring to Fig. 3 in which like parts are designated bythe same reference characters as in the other figures. Assuming that thecontroller occupies its off position and the arms 4 and 5 rest against astop 25; if the arm 5 is moved in a clockwise direction by means of thehandle 13, both arms will be operated concurrently and the contactfinger 17 will come into engagement with the ring segment 16 and,afterward, the contact fingers 14 and 15 will respectively engage thesuccessive contact members 2 and 3. Upon the engagement of the finger 17with the member 16, a circuit is established from a positive lineconductor 26 through arm 4, contact finger 17, member 16, conductor 27,field magnet winding 28 of the motor 29 and conductor 30 to the oppositeline conductor 31. A full field connection is thus established and ismaintained as long as contact finger 17 engages the segment 16. Thecontact fingers 14 and 15 are next brought into engagement with thecontacts 2 and 3. The engagement of the finger 14 with the contacts 2has no efiect upon the strength of the motor field, so long as the shortcircuit 27 is maintained, but a motor circuit is established from thepositive line conductor 26 through arm 5, finger 15, armature resistance32, conductor 33, armature 34 and conductor 30 to line conductor 31. Theamount of resistance included in the armature circuit is graduallydecreased as the finger 16 successively engages the contacts 3.

Vhen the contact arm 4 finally occupies the position shown in Figs. 1and 3 of the drawings, the short circuit 27 of the field resistance 35is interrupted and the field circuit is established from the arm 5through finger 14 and one of the contacts 2 to the field winding 28,from which point the circuit is completed through conductor 30. The arm5 may be adjusted independently of the arm 4 in a counter-clockwisedirection in order to gradually introduce the field resistance 35 forthe purpose of increasing the motor speed. hen the contact finger 17 ofthe arm 4 is disengaged from the ring segment 16, it moves intoengagement with the contact member 36 which is connected to theconductor 33 and, consequently, when the arm is in this position, thearmature resistance is short circuited. If it is desired to reduce thespeed of the motor by strengthening the motor field, and re-inserting aportion of the armature resistance, the arm 5 may be adjusted to theproper position and the push button switch 11 actuated. Then this isdone, the circuit, which was established from the line conductor 26through the contact arms, conductor 27, magnet 6, resistance 3S,conductor 39, swltch 11 and conductor 40 to the line conductor 31, isinterrupted. Following the deenergizing of the magnet, the arm 4 isreleased and is retracted by the spring 7 until it engages the arm 5which is assumed to be held in position by the attendant. As soon as thearms are together, the push button switch is released and closed so thatthe magnet is again energized and holds the arm 4 in opposition to theretracting spring. If the supply of energy to the motor is temporarilyinterrupted, the electro-magnet will be deenergized and both arms willbe thrown to the ofi' position of the controller by the action of thespring 7, irrespective of the positions.

which they occupy.

The circuit connections for the controller may be modified withoutdeparting from the spirit of my invention, and I desire that suchmodifications and minor structural variations shall be included withinits scope.

I claim as my invention:

1. A controller for electric motors com prising a pair ofresistance-regulating arms adapted to operate together in one direction,means for retracting one of the arms to its off position,electro-responsive means for holding said arm in opposition to saidretracting means, and means carried by the other arm for rendering theholding means inoperative.

2. A controller for electric motors comprising a pair ofresistance-regulating arms adapted to operate together in one direction,a retracting spring tending to throw one of the arms to its offposition, an electro-magnet acting in opposition to the retractingspring for holding the arm in the operating positions of the controllerand a switch carried by the other arm for controlling the circuit of themagnet.

3. In a controller for electric motors, the combination with a pair ofcontact-bearing arms, which are adapted to be manually operated togetherin one direction and one of which may be manually operated independentlyin the other direction, of a retracting sprin acting upon one of saidarms for returning both of them to their ofl position, electro-magneticmeans for opposing the action of the spring, and an electric switchcarried by the second arm for governing the electro-magnetic means.

4. A controller for electric motors comprising a pair of contact-bearingarms, one of which is adapt-ed to successively short circuit the motorfield and the motor armature resistances as it progresses in one direction, and the other of which is adapted to gradually exclude thearmature resistance as it progresses in one direction and to graduallyincrease the field resistance as it progresses in the oppositedirection, an electro magnet for opposing the movement of the firstnamed arm and a switch carried by the ing spring for said first namedarm, an electro-magnet for opposing the action of the 15 retractingspring and a switch carried by the said second named arm for controllingthe energization of the electro-magnet.

In testimony whereof, I have hereunto subscribed my name this 24th dayof Dec., 20 1909.

FLETCHER I). HALLOGK.

Witnesses ALBERT VAN ZANDT, B. B. HINES.

